1. Field of the Invention
This invention relates to an accessory adapted to be releasably attached to a film cassette for photographically recording indicia on a film unit, preferably during its exposure.
2. Description of the Prior Art
In the field of photography it is often important to the photographer that certain indicia be photographically recorded on a film unit at the time of its exposure. This indicia may be indicative of the date of the exposure or the speed and/or the aperture setting of the camera's shutter assembly. For example, U.S. Pat. No. 2,403,911 describes a camera system which is used to photographically record on a strip of film the date of its exposure and certain other indicia pertaining to the event being photographed. Several years later, U.S. Pat. No. 3,082,424 described an improved system wherein similar indicia was photographically recorded on a strip of film by passing the film over and in contact with a cylinder having the indicia on its circumferential surface thereby obviating the need for a lens to focus the indicia onto the film. At the appropriate time, the indicia on the cylinder would be back lighted thereby recording the image of the indicia onto the portion of the film strip in contact with the surface of the cylinder. While this latter system did away with one lens, it also created a problem of possible slippage between the surface of the cylinder and the strip of film.
The versatility of recording systems of the type described was further enhanced by the disclosures in U.S. Pat. Nos. 3,843,956 and 4,001,846. The U.S. Pat. No. 3,843,956 discloses a detachable camera back having an indicia recording system mounted therein. The camera back may be used to replace the conventional back of a camera such as a Nikon model F. The recording system uses a display including a plurality of LEDs for photographically recording indicia such as aperture and speed settings on the film unit being exposed. The U.S. Pat. No. 4,001,846 represents an improvement over the system described in the U.S. Pat. No. 3,843,956 in that it provides a means for diffusing the light from the display. However, while the latter two systems have increased the versatility of recording systems they fall far short of the apotheosis in that they are still an integral part of a camera.